721. In Vitro Activity of Cefiderocol Against Gram-Negative Clinical Isolates From New York City

BACKGROUND: Multidrug-resistant Gram-negative bacteria have become a serious problem in hospitals worldwide. Cefiderocol (CFDC) is a novel siderophore cephalosporin with activity against a wide range of carbapenemase- and ESBL-producing bacteria. We tested the activity of CFDC against (1) a recent collection of clinical isolates and (2) a separate collection of carbapenem-resistant isolates gathered from NYC hospitals. METHODS: Susceptibility testing was performed on isolates of E. coli, K. pneumoniae, Enterobacter spp., P. aeruginosa, and A. baumannii gathered in 2017 from 7 hospitals in Brooklyn, NY. Consecutive unique patient clinical isolates from all sources were collected for a three month period. Testing was also done on a collection of carbapenem-resistant isolates from a similar surveillance study conducted in 2013–2014. MICs were performed with iron-depleted cation-adjusted Mueller–Hinton broth for CFDC and agar dilution for other antibiotics according to CLSI methodology. The provisional CLSI breakpoint (≤4 μg/mL susceptible) was used for CFDC. Cephalosporin-resistant isolates were tested for common carbapenemases by PCR. RESULTS: The susceptibility results for CFDC and meropenem for the isolates gathered in 2017 are listed in the Table. All of the Enterobacteriacae were susceptible to CFDC including KPC-possessing E. coli (n = 4), K. pneumoniae (n = 20), and Enterobacter spp (n = 3). 99.6% of P. aeruginosa and 100% of A. baumannii (including 8 with bla(OXA-23), 2 with bla(OXA-24), and 1 with bla(KPC)) were susceptible to CFDC. For the collection of carbapenem-resistant isolates gathered in 2013–14, 100% of K. pneumoniae (n = 111), 100% of P. aeruginosa (n = 130), and 90% of A. baumannii (n = 78) were susceptible to CFDC. CONCLUSION: CFDC has excellent in vitro activity against Gram-negative clinical isolates from NYC, including a large collection of carbapenem-resistant Enterobacteriaceae, P. aeruginosa, and A. baumannii. [Image: see text] DISCLOSURES: All authors: No reported disclosures.